Posted on 01/28/2004 4:41:05 PM PST by blam
Ok, I now admit that I was totally wrong.
The correct question should be:
What Universe do you live in?
This itself presents a question: a) from whom and b) how would the 'uncivilized' world here about this? This presumes, does it not, that a) these 'peoples' have no modern means of communications and b) would they believe it if they heard it? (Some of these 'peoples' are as dubious of their 'news readers'/governments as we are - verily, what is to be believed til one sees the very 'whites of its eyes'?)
Can anyone validate this?
When we are scuba diving, the water has absorbed the red light and everything underwater has a blue tint.
Nobody had altered the colors captured by our underwater camera, but they are different from what we see on the surface..
Question: Is this the exact same thing happening on Mars, but in reverse? Blue light is being filtered out and everything has a red tint?
Until you feel its 'sweaty breath' on your neck, though, there's no cause for worry ;^0
aw, geez, not THAT stupid phrase again... ugh
The key word to research is Mie scattering.
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What about the Martian sky?
The moon's sky is black because it has no atmosphere. The earth normally has a blue or a gray sky, depending on cloud cover. On earth, sometimes windy storms swirl dust into the air, making the sky a hazy tan. Similarly, Mars' atmosphere always contains a lot of dust, and its sky is permanently tan.
On Mars, photographs from both landers (the Viking from 1976-78 and the Pathfinder in 1997) suggested that the sky is always a butterscotch tan color. Mars appears to have a permanent haze of dust, which remains suspended in the air after duststorms. The dust is the mineral "limonite," a brown iron oxide, the same mineral that forms most of the Martian surface. The sky is not blue as on Earth because Martian air is extremely thin and the limonite particles in the air are large relative to the wavelength of visible light. The reddish particles preferentially absorb blue light and effectively act as mirrors by scattering the remaining wavelengths: the color of the atmosphere is therefore pinkish, like the particles themselves.
The Martian daytime sky is generally a butterscotch (yellow/brown) color. We know this from properly color-balanced pictures taken by the Viking landers in 1976 and Mars Pathfinder in 1997. The first Viking Lander images to be broadcast over TV in the 1970s showed a blue sky, later "corrected" to a pink sky. This was because of uncertainties in the initial image processing. Also, the lander had several color patches to calibrate the cameras which were partially covered with Martian dust thrown up during landing. However, further careful analysis of Viking Lander data revealed a Martian sky which is generally "butterscotch" (yellow/brownish) in color, except for the pink/red of sunset and sunrise. This was confirmed by Mars Pathfinder in 1997.
On Mars, pictures taken from the surface by the two Viking lander spacecraft showed a sky which was a yellow color. Measurements also showed that the Martian atmosphere always had some fine dust suspended in it. The dust particles vary in size from smaller than visible wavelengths (0.4 - 0.7 µm) to as large as several tens of µm. Sky color measurements from Viking Lander 1 have been used with computer simulations of light scattering to estimate that the dust particles contained about 1% by volume of an iron oxide mineral known as magnetite (a black, opaque material). This mineral absorbs sunlight more effectively at blue wavelengths than at red wavelengths. Scattering (including absorption) of sunlight by the dust particles in the Martian atmosphere therefore accounts for the sky color. The scattering is more complicated than the simple Rayleigh case because the dust particles both reflect and absorb the sunlight, and because the presence of 'large' particles leads to more uniform scattering among the different wavelengths. If the dust did not absorb any sunlight, the Martian sky would appear whitish, since all wavelengths would be scattered to similar degree, much like sunlight scattered by clouds. The atmospheric dust which provides the pink-yellow tint to the Martian sky is also responsible, due to its ubiquitous presence on the martian surface, for producing the characteristic red color of Mars seen by the naked eye. In general, Rayleigh scattering is a very small effect in the Martian atmosphere However, at certain times and in certain places, clouds of extremely small dust particles give a blue cast to images taken from overhead. These are the so-called "blue hazes" observed in some cratered regions and parts of the Valles Marineris.
If the Martian atmosphere were to be completely cleansed of dust, the daytime sky would appear blue, just as our own sky because of Rayleigh scattering by the molecules (primarily carbon dioxide molecules) which make up the atmosphere. It is possible (though unlikely) that future missions to Mars will find a different sky color.
Give a scientist a low cost optical spectrometer on a Mars robot and this question would be solved in less than 30 minutes.
Mie scattering is the key to this subject. Be advised, this is an advanced topic and there will not be much available on the internet.
Remember, no human on the surface of Mars will ever be in contact with the natural physical environment. Sitting only one foot away from a rock on Mars, an Astronaut is still forced to manipulate items remotely.
The only difference between an Astronaut and a Robot on the surface of Mars is...
20 minutes?
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